Selective Protection and De-Protection of Phenolic Hydroxyl Groups of Naringenin

assessment of deep word knowledge in elementary and advanced iranian efl learners: a comparison of selective and productive wat tasks

testing plays a vital role in any language teaching program. it allows teachers and stakeholders, including program administrators, parents, admissions officers and prospective employers to be assured that the learners are progressing according to an accepted standard (douglas, 2010). the problems currently facing language testers have both practical and theoretical implications but the first i...

commuting and non -commuting graphs of finit groups

فرض کنیمg یک گروه غیر آبلی متناهی باشد . گراف جابجایی g که با نماد نمایش داده می شود ،گرافی است ساده با مجموعه رئوس که در آن دو راس با یک یال به هم وصل می شوند اگر و تنها اگر . مکمل گراف جابجایی g راگراف نا جابجایی g می نامیم.و با نماد نشان می دهیم. گرافهای جابجایی و ناجابجایی یک گروه متناهی ،اولین بار توسطاردوش1 مطرح گردید ،ولی در سالهای اخیر به طور مفصل در مورد بحث و بررسی قرار گرفتند . در ،م...

A General Method for Selective Tritylation of Primary Hydroxyl Groups in Carbohydrates and Related Compounds

A general and rapid procedure is developed for the selective tritylation of the 'primary OH-function of the four common ribonucleosides, ascorbic acid, and polyhydric compounds. Silver ion was found to have a marked effect on tritylation reactions

The synthesis of Beta-Carbonhomologous Intermediate of Norcardicin A. A General Method for Selective Preparation of The Beta-Lactam Ring in the Presence of Free Phenolic Hydroxyl Groups

The synthesis of cis-N-[a-carbobenzyloxy-b-(p-hydroxyphenyl)ethyl]-3-phthalimido-4-styryl-2-azetidinone is described. We have found that the electron-rich Schiff bases can afford the cis-b-lactam ring even in the presence of the free hydroxyl functions. The mechanisms of cis and trans-b-lactam ring formation are discuss...

Radiological protection of patients